Wowee, I just went through hell to sign up to this website just to reply to this. IDK why I did it. Took me 20 Minutes.
If you're googling this error and are here like me, then you deserve it, because you didn't read the instructions for installing ROTLK.
From the instructions: https://forums.revor...allation-guide/
"RotWK needs BfME 2 version 1.06 installed. Use the BfME 2 Patch 1.09 Switcher to change to version 1.06."
Yeah, that's why your error is showing up. So go and change your patch to 1.06 with the patch switcher from II and it should launch now. You're welcome.
P.S Revora, your website told me I entered the captcha wrong about 30 times before I finally got it right, just so I could sign up. How about switching to a captcha that actually works? Thanks. 
P.P.S: I wasn't entering the captcha wrong, it was just broken I swear!
Edited by Amnesiac, 24 April 2019 - 02:11 AM.